Combined electric continuity checker and flashlight

ABSTRACT

Combined flashlight and continuity checker having a generally tubular body for containing one or more flashlight cells provided with a lamp head at one end portion for projecting a beam of light forwardly of the housing having a colored light transmitting rim to enable a lighted condition to be visually observed from a wide angle; a switch mounted at the side of the housing for manual operation of the lamp head; and a socket at the other end portion of the housing connected in parallel with the switch for receiving plug bodies, such as plug-type fuses therewithin to indicate the presence or absence of a complete circuit therethrough by the lighted or non-lighted condition of the lamp head. Adaptors may be provided for checking different types of plug fuses and for providing test leads which may be used for checking continuity of other electrical devices.

United States Patent 1191 11] 3,711,768 Frazin 51 Jan. 16, 1973 [S4] COMBINED ELECTRIC CONTINUTTY Primary Examiner-Gerard R. Strecker CHECKER AND FLASHLIGHT Attorney-Lackenbach & Lackenbach [76] Inventor: Benjamin Frazin, 333 East 176th Street, New York, NY. 10033 [57] ABSTRACT [22] Filed: April 5 1971 Combined flashlight and continuity checker having a generally tubular body for containing one or more PP 131,287 flashlight cells provided with a lamp head at one end portionfor projecting a beam of light forwardly of the [52] US. Cl..... ....324/ 53 housing having a colored light transmitting rim to 511 Int. Cl. ..1. ...c011- 31/00 ble a lighted eenditien be visually ebserved frem a [58] Field of Search ..324/53 Wide angle; a Switch meumed the Side ef the ing for manual operation of the lamp head; and a [56] References Cited socket at the other end portion of the housing connected in parallel with the switch for receiving plug UNITED STATES PATENT bodies, such as plug-type fuses therewithin to indicate the presence or absence of a complete circuit 2,902,643 9 1959 P l ..324 53 3,145337 8x964 3:8 3: 1 "0324553 therethrough by the lighted or n0nl1ghted condition 1,560,278 11/1925 Mahan ..324 53 of the p head- Adaptors y be Provided for 2,832,930 4/l958 Hays ..324/53 checking different types of plug fuses and for providl,508.990 9/1924 Schmidt /53 ing test leads which may be used for checking conl,528,709 3/l925 Trimble "324/53 tinuity of other electrical devices. l,372,570 3/1921 Smith ..324/53 6 Claims, 4 Drawing Figures 38, I 53/4 WI 1 22 66 52;. 74 72 88 76 n I06 96 728' I04 102 96 COMBINED-ELECTRIC CONTINUITYCHECKER AND FLASHLIGHT- This invention relates to new and improved combined electrical flashlight and continuity checkers.

A primary .object of the present invention is the provision of novel and improved combined electric flashlight and continuity checkers constructed and arranged for maximum utility and ease of operation-in either mode.

Another primary object of the present invention, in addition to the foregoing object, is the provision of such combined electric instruments in a single housing which may be readily and easily utilized in either mode without requiring any modifications or adjustments from one mode to the other.

Yet anotherprimary object of the present invention, in addition to each of the foregoing objects, is to provide instruments of the class described which may be readily and easily utilized without requiring any com: plex training in their use.

Yet further, it is another primary object of the present invention, in addition to each of the foregoing objects, to provide instruments of the class described which are economical to manufacture and durable and efficient in use. I

Yet still further, it is another primary object of the present invention, in addition to each of the foregoing objects, to provide instruments of the class described particularly adapted to enable rapid and efficient checking of electrical devices having plug bodies and particularly electric plug-type fuses.

Still further, it is yet another primary object of the present invention, in addition to each of the foregoing objects, to provide instruments of the class described with a socket for receiving a plug body and indicating the presence or absence of electrical continuities therethrough so that a fuse may be directly inserted in such socket and its condition readily and easily determined or an adaptor inserted therein having a dual parallel blade socket, for example, to receive a conventional line cord of an appliance for determining the presence or absence of electrical continuity therethrough or a plug body having a pair of test leads extending outwardly therefrom for checking continuity of diverse electrical devices.

Yet another and still further primary object of the present invention, in addition to each of the foregoing objects, is the provision of such electrical instruments wherein the indication of the presence or absence of continuity may be readily visually discerned from widely diverse angular positions.

The invention resides in the combination, construction, arrangement and disposition of the various component parts and elements incorporated in novel and improved combination electrical flashlights and conof practicing the principles thereof. Other embodiments or modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modifications are intended to be .reserved especially as they fall within the scope and spirit of the subjoined claims.

IN THE DRAWING:

FIG. 1 is a perspective illustration of a combined electrical tester and continuity checker constructed in accordance with the principles of the present invention;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is an elevational view, partially in section, illustrating a test lead adaptor which may be utilized for checking electrical continuity of devices and apparatus which cannot be inserted into the checker socket; and

FIG. 4 is a partial cross-sectional view, similar to the lower portion of FIG. 2, illustrating another embodiment or modification of a combined electrical tester and continuity checker constructed in accordance with the principles of the present invention.

With reference now to the drawing, and particularly to FIGS. 1 and 2 thereof, there is shown and illustrated a combined electrical flashlight and continuity checking instrument constructed in accordance with the principles of the present invention and designated generally by the reference character 10.

The instrument 110 may comprise a generally cylindrical housing 12 provided at one end portion with a lamp head 14 for projecting a beam of light generally forwardly of the housing 12 and a socket 16 at the other end portion thereof for receiving therewithin the threaded base of a plug body, as will be described in more detail hereinafter, for checking the electrical continuity therethrough. The housing 12 may be constructed and arranged to contain therewithin one or more flashlight type electrical energy cells, such as a pair of cells 18 in back to back series relationship and may be provided with a manually operable switch 20 for enabling selective energization of the lamp head 14 in a manually operable or flashlight mode.

The lamp head 14 may comprise, for example, a

' generally bell shaped housing or mouth portion 22 havtinuity checkers constructed in accordance with the principles of this invention. The present invention will be better understood and objects and important features other than those specifically enumerated above will become apparent when consideration is given to the following details and description, which when taken I ing a generally open and unobstructed mouth opening 24 structurally associated with the cylindrical or tubular housing portion 12 in general axial alignment therewith and with the mouth opening 24 extending generally forwardly thereof. Disposed generally within the mouth portion 22 there may be provided a lens and reflector assembly 26 comprising, for example, a generally parabolic reflector 28 having a generally annular rim portion 30 extending generally laterally outwardly of the forward edge portion thereof and a lamp socket 32 at the rearward apex thereof for supporting a flashlight type electric lamp 36 with the filament 38 thereof generally at the focus of the reflector 28. Disposed generally forwardly of the reflector 28 and extending generally transversely across the reflector and the mouth opening 24 of the lamp head 14 there may be provided a generally circular lens or cover 40 fabricated of transparent material. The lens or cover 40 may be of a plain, flat configuration or may comprise curved surfaces for focusing the light admitted by the lamp 36. Further, there may be provided a retaining ring 42 of generally cylindrical configuration having a generally inwardly extending annular retaining portion 44 adapted to engage the outer edge portion of the lens 40. The ring 42 may be provided, for example, with internal thread means 46 adjacent the rearward edge portion thereof for engagement with generally external threads 48 provided adjacent the forward end portion of the bell or mouth housing portion 22 so that upon assembly of the retaining ring 42 therewith, the lens 40 will be clamped between the annular portion 44 of the retaining ring 42 and the annular rim 30 of the reflector 28 and the annular rim 30 of the reflector 28 in turn clamped against the forward edge of the mouth or bell housing 22.

Preferably, the retaining ring 42 is fabricated of a material which is at least translucent and, preferably, colored so that upon lighting of the lamp 36, a portion of the light emitted thereby will be diffused through the retaining ring 42 to cause a glow to be emitted substantially entirely thereby which may be readily and easily visually discerned from substantially any viewing angle and even from the rear of the instrument 10.

As heretofore pointed out, the energy cells 18 and the lamp 36 are preferably of the well known flashlight type and, accordingly, will not be described further except to point out that the energy cells 18 would generally comprise a center electrode terminal 50 projecting generally centrally forwardly thereof with the rearward end surface 52 comprising a shell or casing electrode terminal thereof and with the side edge portion being electrically insulated, as by means of a paper wrapping, or the like and the lamp 36 comprises a base portion having a shell terminal 54 connected with one end portion of the filament 38 and a tip terminal 56 connected with the other end portion of the filament 38 and insulated from the shell terminal 54 as by means of insulating material 58 disposed therebetween. The shell terminal 54 may be of either the screw threaded type or may comprise a bayonet type base, as shown.

The socket 32 may comprise a generally cylindrical portion 60 projecting generally rearwardly of the reflector 28 and if it is desired to utilize a lamp 36 of the screw-based type, then all that is necessary to define the socket 32 is to provide generally inwardly extending internal screw threads on the cylindrical or sleeve portion 60 so that the lamp may be screw threadedly engaged therewith from generally internally of the reflector 28 so that the tip terminal 56 thereof engages the center electrode terminal 50 of the forwardmost one of the energy cells 18. If, however, as shown, a bayonet based lamp 36 having an annular rim 62, then a retainer ring 64 must be provided to screw threadedly engage the sleeve or cylindrical portion 60 and clamp the rim 62 against the reflector 28 while disposing the tip terminal 56 for engagement with the center electrode terminal 50 of the energy cell 18. Disposed generally rearwardly of the energy cell 18, there may be provided means for urging the cells forwardly so that the center electrode terminals 50 of each of the rearward cells will be firmly engaged with the shell or casing electrode 52 of the next preceding energy cell and so that the center electrode terminal 50 of the forwardmost one of the energy cells 18 will firmly engage the tip electrode 56 of the lamp 36. The biasing means may comprise a generally conical coil spring 66 having its apex engaged with the shell or casing electrode of the rearmost one of the energy cells 18 and the base of substantially similar diameter to the inside diameter of the generally tubular casing 12 and engaged therewith so that the housing 12 is electrically connected with and at the same potential as the casing electrode terminal of the rearmost one of the energy cells. Accordingly, it is believed readily obvious that all that is necessary to light the lamp 36 is to provide a path of electrical conductivity between the housing 12 which, preferably, comprises a metal or other electrically conductive material and the shell terminal 54 of the lamp 36. To provide such a path, while yet enabling control of the lighting, the socket cylindrical portion 60 may be fabricated of a metal or other conductive material so as to provide a path of electrical contact to the shell terminal 54 of the lamp 56. The reflector 28 may similarly be fabricated of metal or other conductive material and insulated from the housing, as by being supported within a non-conductive gasket extending along the rim 30 thereof or, the reflector 28 may comprise a non-conductive material, such as plastic having a reflective coating, for example, a metallizing coating applied to the interior thereof and having a metallized generally outwardly extending rearward portion 68 disposed thereon and electrically and mechanically connected with the socket sleeve or tubular portion 60. A strip or spring terminal 70 may be provided physically mounted with the housing 12 but electrically insulated therefrom, as by means of a fiber or insulating strip 72 and having a cantilevered end portion 74 adapted for contacting the metallic portion 68 of the reflector assembly. The housing 12 may, for example, be provided with a plurality of apertures 76 and 78 through which tabs 80 and 82 cut from the fibrous strip 72 along generally U-shaped cutting lines may project and tabs 84 and 86 similarly cut from the metallic strip 70 and crimped thereover for supporting the metallic strip 74 in position while electrically insulated from the housing 12. A switch cover 88 may be secured with the housing 12 generally above the tabs 80-86, as by having a tab 90 thereof engaged through an aperture 92 provided generally forwardly of the aperture 76 for retaining the forward end portion of the switch cover 88 and a rivet 94 extending through the switch cover 88 and the housing 12 adjacent the rearward end of the switch cover 88. A contact terminal 96 fabricated, for example, of sheet metal or the like may be disposed within the switch cover 88 and mechanically connected with a switch handle 98, as by means of bent tabs 102 extending inwardly from the switch handle 98 through elongated generally longitudinally extending slots provided in the switch housing 88 so that upon forward sliding movement of the switch handle 98, the terminal member 96 will move forwardly and rearwardly therewith. The switch housing 88 and the terminal strip 96 preferably comprise conductive material so that the terminal strip'96 is electrically connected with the housing 12 and at the same potential therefore as the potential of the casing electrode of the rearmost one of the energy cells 18. The switch housing 88 may be provided with a pair of dimples extending generally outwardly for cooperation with a dimple 106 projecting generally inwardly from a detent plate 108 provided within the switch handle 98 so as to define three distinct positions for the switch handle 98, namely, a rearward position, a central position and a forward position. Further, the switch housing 88 may be provided with a generally circular aperture 111 through which a button 113 projects. The contact terminal 102 is preferably configured to have contact portions 110 and 112, respectively, at each end portion thereof spaced apart a distance such that, in the rearward position of the switch handle 96 and, therefore, in the rearward position of the switch terminal 1112, neither one of the contact portions 110 nor 112 will be engaged or en- 'gageable with the tabs 84 and 86; so that with the switch handle 98 in the centermost position thereof, the forwardmost one of the contact portions 1 will be disposed in general alignment and in spaced apart relationship to the forward tab 84 so that upon depression of the push bottom 113, it will contact the tab 84 and thereby provide a complete electric circuit between the tab 84 and associated contact strip 70 and the housing 12; and, with the switch handle 98 in the forwardmost position, the rearward contact portion 112 will be engaged with the rearward tab 86 to place the tab 86 and the associated strip 70 in electrical communication with the housing 12. Hence, therefore, an intermediate position for the switch may be defined whereat the lamp will be lighted only upon depression of the push button 113 and a constant on position wherein the lamp 36 will remain lighted continuously, both in addition to the rearward off position wherein the lamp 36 will not be lighted.

As heretofore pointed out, the instrument 10 is further provided with a socket 16 connected in generally parallel electrical connection with the switch 20 and particularly adapted to receive therewithin the base of an electrical device, such as a plug type fuse and indicate, by the lighting or failure to light of the lamp 36 the presence or absence of a complete electrical circuit therethrough. Such socket may be defined, for example, by a metallic cap screw threadedly connected with the rearward end portion of the housing 12 and provided with a generally internally threaded aperture 114 extending generally axially inwardly thereof. The screw threaded aperture 114 may be in substantially any desired aperture or pitch to mate with substantially any desired electrical device. Preferably, however, the aperture 114 is of such diameter and pitch as to mate with a plug fuse of either the Edison base or the type S tamper proof type.

As illustrated, the aperture 114 may be of a standard Edison base threaded so that standard plug fuses may be inserted therein for checking, a standard plug body inserted therein having, for example, a pair of parallel slots for receiving a conventional appliance cord therein, for receiving an adaptor having an Edison base and a pair of test leads extending outwardly thereof for enabling checking of continuity through diverse electrical devices or for receiving an adaptor, such as an adaptor 116 having external Edison base threads and an aperture 118 for receiving therein the base of a type S tamper proof fuse.

Type S tamper proof fuses, such as those sold under the trademark FUSESTAT" are fuses having a smaller body diameter than the conventional Edison base plug type fuse with different pitched threads being utilized for different amperage fuses so that only a limited range of fuse may be inserted and fuses having an amperage rating greater than the safe carrying capacity of the connected wires may not be inserted. For example, one pitch of thread is utilized for fuses having a rating from 7 V2 to l5 amps, such as for lighting circuits and a different pitch thread is utilized for fuses having ratings from 20 to 30 amps, such as for appliance circuits. In the present tester or checker, however, it is desirable that either type of type S fuse be readily and easily checked without requiring that the adaptor be changed or that a different cap or socket be utilized for each of the different types of Type S fuses. This can be accomplished, for example, by providing only a relatively short inwardly turned edge portion adapted to extend between two adjacent thread crests so as to be substantially independent of the pitch of the threads with the remainder of the aperture in the adaptor being of sufficient diameter that the thread crests pass therethrough without interference. Hence, Type S fuses of substantially any pitch may be inserted therein for test purposes. The edge 1211 may comprise a sheet surrounding the entire adaptor so that a complete electrical circuit will be provided to the housing 12 for engagement by the contact ears 122 of the type S fuse. Of course, various spring means may be provided, rather than the screw threaded means in the apertures so that devices such as fuses may be merely inserted into and withdrawn from the aperture without requiring that they be screw threadedly inserted therein. However, so that various adaptors may be readily and easily inserted and retained therein, including adaptors such as that depicted in FIG. 3 having a pair of test leads extending outwardly thereof, it has been found preferable to provide such screw thread means.

Generally within the housing 12, and adjacent the rearward end thereof, there may be provided a generally cylindrical cup 124 fabricated of insulated material, such as plastic, or the like, generally embodying the conical spring 66. Disposed generally within the cup member 124, there may be provided a second generally conical spring 126 having its apex extending generally rearwardly thereof and having a contact or terminal portion defined, for example, by a rivet or screw 128 secured with the apex thereof to provide the center terminal or contact of the socket 16. The terminal or contact 128 may be electrically connected with the terminal strip 70, as by the strip 70 extending substantially entirely longitudinally of the housing 12 while spaced apart therefrom by the fiber strip 72, as shown and with the rearward end portion of the terminal strip 70 being bent generally inwardly and secured with the contact terminal 128. Of course, a flexible, insulated wire may be connected between the terminal 128 and the strip 70, if desired.

The energy cells 18 may be removed and replaced by removing the lens and reflector assembly/As an aid in removing and retaining the energy cells 18, a sleeve 130 may be provided for joining a plurality of such energy cells together into a single easily handled unit.

As'heretofore pointed out, it is within the ambit of the present invention to provide, in addition to the adaptors heretofore described in detail, an adaptor which may be inserted into the socket 16 having a pair of bodily flexible elongated test leads associated therewith for enabling the performance of continuity checks on diverse electrical devices and appliances. Such adaptor may be provided having a conventional Edison base plug body where the socket 16 is constructed to receive such a plug body or, for use where the socket 16 is constructed to receive the Type S fuse base or where an adaptor is provided for receiving such fuse bases, the test lead adaptor may be provided with a type S fuse base.

Accordingly, and with reference now to FIG. 3, there is shown and illustrated an exemplary test lead adaptor having a type S fuse base constructed in accordance with the principles of the present invention and designated generally by the reference character 130. The adaptor 130 may, for example, comprise a plastic or ceramic body 132 having a cavity 134 therein and comprising, in turn, a generally cylindrical base portion having external threads 136 molded therewith and a head portion having a generally peripherally extending groove 138 extending therearound. An aperture 140 may be provided extending through the bottom of the base portion and a metallic contact having a button head 142 disposed generally beneath the plug body and a stem 144 extending through the aperture into the cavity may be provided for contacting the socket terminal 128. A flexible electrical conductor 146, preferably provided with an insulating flexible sheath 148 may be mechanically and electrically connected with the contact stern 144, as by means of a pool of solder 150, or the like, providing a mechanical joining of the wire 146 and the contact 144 and further retaining the contact 144 in position. The wire 146 may ex tend generally outwardly through the head portion of the adaptor plug body 132 and be provided at its outboard end with terminal means, such as a test prod or test clip, such as a test clip 152.

Disposed generally beneath the head portion of the plug body, there may be provided a generally U-shaped contact terminal 154 having a generally upstanding portion extending through an aperture 156 provided in the head portion of the plug body 132 and into the cavity 134 whereat a second test lead or wire 158 provided with an insulating sheath 160 may be mechanically and electrically connected therewith, as by means of a pool of solder 162, or the like. The outboard end portion of the test lead or wire 158 may be similarly provided with a terminal, such as a test prod or alligator clip 164. A metallic cap 166 may be provided extending across the open end of the cavity 134, having its rim crimped into the head groove 138 and provided with a generally central aperture 168 provided with a rubber grommet 170, or the like, through which the wires 146 and 158 may extend. lf desired, the test leads or wires 146 and 158 may be retained together for at least a part of their extent by means of an oversheath, 172.

A somewhat simpler construction, utilizing cantilevered flat springs rather than conical coil springs for making contact with the energy cell and the device being tested is shown and illustrated in FIG. 4. The embodiment or modification of the instrument illustrated in FIG. 4 may be substantially the same as that of the preceding figures, except where specific differences may be hereinafter set forth and, accordingly, like reference characters have been utilized with the exception that those component parts and elements which have been modified are indicated by having the reference characters associated therewith being primed.

Bearing in mind the foregoing, a generally flat spring 66 formed to define a substantially right angle portion having one leg generally longitudinally adjacent the interior of the housing 12 and secured thereto, both electrically and mechanically, as by means of one or more fasteners, such as rivets 174 and a second leg at substantial right angles thereto extending generally across the housing 12 for contacting the casing electrode terminal of the rearmost one of the energy cells and urging such energy cell generally forwardly. Accordingly, the spring 66' perform substantially the same function as the conical coil spring 66, urging the energy cells forwardly and providing a path of electrical communication between the casing electrode terminal of the rearmost one thereof and the housing 12. The lower end portion of the terminal strip 70 may, as shown, be extended and formed generally inwardly to define a spring portion 126 extending generally across the housing 12 adjacent the socket or end cap 16 having a generally centrally disposed contact portion 128' formed thereon. The insulating strip 72' may similarly be extended, as shown, so as to insulate the spring portion 126 and contact portion 128' from accidental contact with the housing 12 and socket or end cap 16. The spring portion 66' may be insulated from accidental contact with the spring portion 126', as by means of a fiber or plastic strip 124 disposed generally therebetween and secured, for example, by means of the rivets 174.

While the invention has been described, disclosed, illustrated and shown in terms of embodiments or modifications which it has assumed in practice, the scope of the invention should not be deemed to be limited by the precise embodiment or modification herein described, disclosed, illustrated or shown, such other embodiments or modifications as may be suggested to those having the benefit of the teachings herein being intended to be reserved especially as they fall within the scope and breadth of the claims here appended.

What is claimed is 1. Electrical continuity checker for determining the presence or absence of a complete electrical circuit through an electrical device such as a plug-type fuse comprising, in combination, a generally cylindrical housing comprising, in turn, electrically conductive material for containing one or more flashlight-type electrical energy cells serially therewithin, lamp socket means at one end portion of said housing for receiving the base portion of a flashlight lamp and providing electrical connections thereto, device socket means at the other end portion of said casing for receiving the base portion of an electrical device to be checked and providing electrical connections thereto and electric circuit means mounted with said housing for placing said lamp and device socket means in series with said energy cells as may be contained within said housing so that such lamp will light only if such device comprises a complete electrical circuit and switch means and electrical parallel connection across said device socket for bypassing such device socket and enabling selective manual lighting of such lamp, said switch means comprising a first contact electrically connected with one terminal of said lamp socket and a second contact electrically connected with said housing, said electric circuit means comprising a spring battery contact connected with said housing for engaging the rearmost casing electrode of such energy cells and conductor means connecting said first switch contact with one terminal of said device socket, the other terminal of said device socket being electrically connected with said housing wherein said lamp socket comprises a dish reflector having a central electrically conductive portion for engagement by said first switch contact provided with an aperture at the base thereof and means adjacent said aperture for engaging the shell terminal of such flashlight lamp to position the globe portion thereof within the reflector generally at the focus thereof and the tip terminal thereof projecting rearwardly for contact with the forwardmost center electrode terminal of such energy cells, said spring contact comprising a conical coil spring having the base thereof engaged with said housing and the apex projecting generally forwardly for urging such cells toward engagement with such lamp and said device socket means comprises an insulator disposed within said housing generally rearwardly of said cell contact spring, and means extending across said housing rearwardly of said device socket spring provided with an aperture in general axial alignment therewith for enabling the base of such device to be inserted therethrough so that the shell terminal thereof is electrically connected with said housing and the base terminal is engaged by said device socket spring, and wherein said one terminal of said device socket comprises a conical device socket coil spring having the base thereof engaged with said insulator and electrically insulated thereby from said housing with the apex thereof projecting generally rearwardly.

2. Checker defined in claim 1' wherein said last-mentioned means comprises a rear electrically conductive cap screw threadedly engaged with said housing provided with means for defining internal screw threads extending inwardly of said aperture for threadedly receiving and providing electrical connection to the base shell of such plug-type fuses. I v

3. Checker defined in claim 2 furthercomprising a lens and retaining ring assembly screw threadedly engaged with said housing for retaining said reflector therein, said retaining ring comprising translucentmeans 'fo r'conducting a portion of the light produced by 'such lamp generally. transversely outwardly of the beam direction defined by said reflector to enable the visual indication provided thereby to be viewed from widely diverse angular positions. I

4. Checker defined in claim Zwherein said screw threaded aperture of said rear cap is configured to receive an Edison based-plug'bodyand further comprising an adaptor receivable therein having external threads conforming to an Edison base plug body and a recess for receiving a type S plug body, making electrical connections therebetween and provided with a single, inwardly extending, relatively short helically disposed thread portion to mate and engageany of a plurality of diversely pitched threads such as are utilized on such type S fuse plug bodies.

5. Checker defined in claim dyet further comprising an adaptor havinga type .S plug body and a pair of flexible insulated conductors connected with the respective terminals thereof for checking electrical continuity of devices which are not receivable within the device socket.

6. Instrument for use as a flashlight and as an electrical continuity checker comprising, in combination, a generally cylindrical metallic housing for containing at least one flashlight-type energy cell generally axially therewithin and provided with a generally forwardly directed generally open and unobstructed mouth portion at one end of said housing, a lamp assembly removably disposed within said mouth portion and comprising means for supporting a flashlight lamp with the base thereof projecting generally axially rearwardly for contact between the base terminal of the forwardmost energy cell and comprising, in turn, an inwardly dished reflector having a generally annular rim extending generally co-axially forwardly of the forward edge of said cylindrical housing for projecting the light rays from such lamp generally beamwise from said housing, a generally circular transparent cover extending generally co-axially forwardly across said rim to protect said reflector from dirt and a generally annular translucent light conducting retaining ring screw-threadedly engaged with the forward edge portion of said housing for clamping said cover and reflector rim against said housing forward edge and diffusing a portion of the light from said lamp generally radially of the housing and reflector axis so that visual indication of lighting of such lamp may be readily discerned from widely diverse angular positions and enable easy removal of said lamp assembly for insertion and removal of such energy cells through said mouth portion and electric circuit means for connecting the shell terminal of such lamp base and the casing terminal of the rearmost energy cell with said housing and comprising, in turn, parallel connector switch and socket means connected in series between said casing terminal and said shell terminal for enabling energization of such lamp upon the presence of a complete circuit through either of said switch and socket means, said switch means being manually operable-and mounted with said housing at an intermediate side portion thereof and said socket means having an opening directed generally axially rearwardly of the housing for receiving therein the plug portion of an electrical device having a plug body, such as a plug-type-fuse, and being provided with means for defining an internal screw thread for threadedly receiving the threaded body of such plug-type fuse, so that the presence of a complete electric circuit through such device will light the lamp and wherein said electric circuit means further comprises a first generally conical coil spring having its base engaging said housing generally medially thereof and its apex extending generally forwardly to engage the casing electrode of 

1. Electrical continuity checker for determining the presence or absence of a complete electrical circuit through an electrical device such as a plug-type fuse comprising, in combination, a generally cylindrical housing comprising, in turn, electrically conductive material for containing one or more flashlight-type electrical energy cells serially therewithin, lamp socket means at one end portion of said housing for receiving the base portion of a flashlight lamp and providing electrical connections thereto, device socket means at the other end portion of said casing for receiving the base portion of an electrical device to be checked and providing electrical connecTions thereto and electric circuit means mounted with said housing for placing said lamp and device socket means in series with said energy cells as may be contained within said housing so that such lamp will light only if such device comprises a complete electrical circuit and switch means and electrical parallel connection across said device socket for bypassing such device socket and enabling selective manual lighting of such lamp, said switch means comprising a first contact electrically connected with one terminal of said lamp socket and a second contact electrically connected with said housing, said electric circuit means comprising a spring battery contact connected with said housing for engaging the rearmost casing electrode of such energy cells and conductor means connecting said first switch contact with one terminal of said device socket, the other terminal of said device socket being electrically connected with said housing wherein said lamp socket comprises a dish reflector having a central electrically conductive portion for engagement by said first switch contact provided with an aperture at the base thereof and means adjacent said aperture for engaging the shell terminal of such flashlight lamp to position the globe portion thereof within the reflector generally at the focus thereof and the tip terminal thereof projecting rearwardly for contact with the forwardmost center electrode terminal of such energy cells, said spring contact comprising a conical coil spring having the base thereof engaged with said housing and the apex projecting generally forwardly for urging such cells toward engagement with such lamp and said device socket means comprises an insulator disposed within said housing generally rearwardly of said cell contact spring, and means extending across said housing rearwardly of said device socket spring provided with an aperture in general axial alignment therewith for enabling the base of such device to be inserted therethrough so that the shell terminal thereof is electrically connected with said housing and the base terminal is engaged by said device socket spring, and wherein said one terminal of said device socket comprises a conical device socket coil spring having the base thereof engaged with said insulator and electrically insulated thereby from said housing with the apex thereof projecting generally rearwardly.
 2. Checker defined in claim 1 wherein said last-mentioned means comprises a rear electrically conductive cap screw threadedly engaged with said housing provided with means for defining internal screw threads extending inwardly of said aperture for threadedly receiving and providing electrical connection to the base shell of such plug-type fuses.
 3. Checker defined in claim 2 further comprising a lens and retaining ring assembly screw threadedly engaged with said housing for retaining said reflector therein, said retaining ring comprising translucent means for conducting a portion of the light produced by such lamp generally transversely outwardly of the beam direction defined by said reflector to enable the visual indication provided thereby to be viewed from widely diverse angular positions.
 4. Checker defined in claim 2 wherein said screw threaded aperture of said rear cap is configured to receive an Edison based plug body and further comprising an adaptor receivable therein having external threads conforming to an Edison base plug body and a recess for receiving a type S plug body, making electrical connections therebetween and provided with a single, inwardly extending, relatively short helically disposed thread portion to mate and engage any of a plurality of diversely pitched threads such as are utilized on such type S fuse plug bodies.
 5. Checker defined in claim 4 yet further comprising an adaptor having a type S plug body and a pair of flexible insulated conductors connected with the respective terminals thereof for checking electrical continuity of devices which are not receivable within the devicE socket.
 6. Instrument for use as a flashlight and as an electrical continuity checker comprising, in combination, a generally cylindrical metallic housing for containing at least one flashlight-type energy cell generally axially therewithin and provided with a generally forwardly directed generally open and unobstructed mouth portion at one end of said housing, a lamp assembly removably disposed within said mouth portion and comprising means for supporting a flashlight lamp with the base thereof projecting generally axially rearwardly for contact between the base terminal of the forwardmost energy cell and comprising, in turn, an inwardly dished reflector having a generally annular rim extending generally co-axially forwardly of the forward edge of said cylindrical housing for projecting the light rays from such lamp generally beamwise from said housing, a generally circular transparent cover extending generally co-axially forwardly across said rim to protect said reflector from dirt and a generally annular translucent light conducting retaining ring screw-threadedly engaged with the forward edge portion of said housing for clamping said cover and reflector rim against said housing forward edge and diffusing a portion of the light from said lamp generally radially of the housing and reflector axis so that visual indication of lighting of such lamp may be readily discerned from widely diverse angular positions and enable easy removal of said lamp assembly for insertion and removal of such energy cells through said mouth portion and electric circuit means for connecting the shell terminal of such lamp base and the casing terminal of the rearmost energy cell with said housing and comprising, in turn, parallel connector switch and socket means connected in series between said casing terminal and said shell terminal for enabling energization of such lamp upon the presence of a complete circuit through either of said switch and socket means, said switch means being manually operable and mounted with said housing at an intermediate side portion thereof and said socket means having an opening directed generally axially rearwardly of the housing for receiving therein the plug portion of an electrical device having a plug body, such as a plug-type fuse, and being provided with means for defining an internal screw thread for threadedly receiving the threaded body of such plug-type fuse, so that the presence of a complete electric circuit through such device will light the lamp and wherein said electric circuit means further comprises a first generally conical coil spring having its base engaging said housing generally medially thereof and its apex extending generally forwardly to engage the casing electrode of the rearmost energy cell, a second generally conical coil spring disposed generally rearwardly of said first spring and electrically insulated therefrom having its apex extending generally rearwardly to define the central contact of said socket means for engaging the base terminal of such device plug body and an electrical conductor connected thereto extending generally forwardly into electrical contact with one terminal of said switch means and with the shell terminal of such flashlight lamp, and wherein the other terminal of such switch is electrically connected with said housing. 